The propfan–swirl recovery vane (SRV) configuration is gaining renewed attention for its potential for higher propulsive efficiency, simpler transmission structure, and lower noise as compared to counterrotating propfans. In this paper, three primary unsteady interference mechanisms were analyzed, focusing on the far-field noise and identifying the contribution of different mechanisms to SRV noise. The results indicate that the propfan tip vortex amplified the pressure differential across the SRV, inducing the tip vortex in the SRV and causing significant load fluctuations, while the secondary flows in the root and viscous wake interference have limited effect. Propfan noise dominates at polar angles from 40° to 145°, while SRV noise is more pronounced at forward and aft polar angles. The maximum noise level of the propfan-SRV was recorded at the polar direction of 95°, reaching 132.03 dB. Spanwise decomposition of the SRV noise sources indicates that the midsection contributes most to the total SRV noise, while the tip region noise remains significant despite limited span extent. Notably, the swept SRV blade design induces phase differences across spanwise sections, leading to effective noise cancellation at specific polar angles. These findings provide valuable guidance for noise reduction design in the propfan-SRV configuration.
Zhu et al. (Thu,) studied this question.